1. Field of the Invention
The present invention relates generally to the field of telephone switching equipment. More specifically, the present invention relates to the management of call detail records in telephone switching equipment.
2. Background of the Invention
A continuing problem faced by cellular telephone companies is monitoring activity on their cellular telephone networks. A significant contribution to this problem stems from the disparate kinds of equipment used in the network. One consequence of the inability to effectively monitor activity in the system is that unbilled activity can occur on the network. This can happen for a number of reasons, including stolen service through a variety of cellular fraud schemes, billing mistakes due to incorrect entry of billing information, manufacturer errors in configuring telephone switches that lead to missed billing opportunities, errors in switch operating systems and poor management that results in improper billing for used services.
Detecting such lost billing opportunities requires analysis of the activity of each switch in the telephone network. Modern cellular telephone switches maintain records for each telephone call the switch is involved in handling. These records are known as call detail records (CDRs). CDRs contain virtually all the information regarding telephone calls handled by the switch, including, for example, identification of trunk group and cell site, duration of the call, start date and start time of the call, termination status of the call and other information related to the call. An enormous amount of information can be stored in the CDRs. For example, in a typical billing cycle of one month it is not uncommon for a switch in a cellular telephone system to generate fifty to one hundred million CDRs.
Extracting this information in a usable form is a significant problem for most cellular telephone systems. One problem is that cellular telephone systems generally are not homogenous systems. That is, many cellular telephone systems comprise switches from more than one manufacturer. While each switch provides CDRs containing detailed information regarding the calls handled by that switch, the CDRs are generated in a format that is proprietary to its manufacturer. For example, some switches generate one CDR per telephone call, while other switches generate one or more CDRs per telephone call. These proprietary formats make it enormously difficult to amass the voluminous CDR information from multiple switches so that call detail analyses can be performed on a system-wide basis, rather than switch-specific basis. Further, CDRs can differ even in a single switch manufacturer's switches. Such differences can result, for example, from different releases of switch software.